Ceramic burner

Abstract

A ceramic burner is provided, particularly for use in a hot-blast oven, with a generally cylindrical wall defining a central burner duct and a housing extending around and spaced from the generally cylindrical wall to define an outer annular duct disposed coaxial to the central burner duct. The generally cylindrical wall includes an inner peripheral surface extending outwardly from a central burner duct to define a burner mouth. First and second ring nozzles are provided having openings extending from the outer annular duct and open at the burner mouth. Nozzle inserts are provided for insertion into the openings of the first and second ring nozzles so as to vary the cross-sectional area defined by the openings of the first and second ring nozzles. Additionally, injector grids are provided for insertion into the openings of the first and second ring nozzles so as to divide each of the openings into a plurality of smaller openings. The ceramic burner may also be provided with a third ring nozzle, extending from the outer annular duct and open at the central burner duct, which is located below the burner mouth.

What is claimed is: 
     
       1. A burner comprising: a wall defining a central burner duct for allowing a first combustion component to pass therethrough in a flow direction;   a housing extending around and spaced from said wall so as to define an outer annular duct disposed coaxial to said central burner duct for allowing a second combustion component to pass therethrough in said flow direction;   said wall having an inner peripheral surface extending outwardly from said central burner duct in said flow direction to define a burner mouth;   said wall having a first ring nozzle placing said central burner duct in communication with said outer annular duct for combining the first and second combustion components, said first ring nozzle including a first plurality of openings extending from said outer annular duct and open at said inner peripheral surface that defines said burner mouth;   said wall having a second ring nozzle placing said central burner duct in communication with said outer annular duct for combining the first and second combustion components, said second ring nozzle including a second plurality of openings extending from said outer annular duct and open at said inner peripheral surface that defines said burner mouth;   said second ring nozzle being located downstream from said first ring nozzle relative said flow direction.   
     
     
       2. A burner as recited in claim 1, wherein each of said first plurality of openings is located approximately equidistant from each adjacent opening of said first plurality of openings, and wherein each of said second plurality of openings is located approximately equidistant from each adjacent opening of said second plurality of openings, and wherein said first plurality of openings are offset along said inner peripheral surface relative said second plurality of openings. 
     
     
       3. A burner as recited in claim 1, wherein a cross-sectional opening area defined by each of said first and second plurality of openings extends a predetermined width and a predetermined length, and wherein a ratio of said predetermined width to said predetermined length is at most 1:4.4. 
     
     
       4. A burner as recited in claim 2, wherein a cross-sectional opening area defined by each of said first and second plurality of openings extends a predetermined width and a predetermined length, and wherein a ratio of said predetermined width to said predetermined length is at most 1:4.4. 
     
     
       5. A burner as recited in claim 1, wherein a cross-sectional opening area defined by each of said first and second plurality of openings extends a predetermined width and a predetermined length, and wherein each of said first and second plurality of openings are respectively spaced from each adjacent opening of said first and second plurality of openings by a distance which is approximately 7 to 8 times greater than said predetermined width. 
     
     
       6. A burner as recited in claim 2, wherein a cross-sectional opening area defined by each of said first and second plurality of openings extends a predetermined width and a predetermined length, and wherein each of said first and second plurality of openings are respectively spaced from each adjacent opening of said first and second plurality of openings by a distance which is approximately 7 to 8 times greater than said predetermined width. 
     
     
       7. A burner as recited in claim 3, wherein each of said first and second plurality of openings are respectively spaced from each adjacent opening of said first and second plurality of openings by a distance which is approximately 7 to 8 times greater than said predetermined width. 
     
     
       8. A burner as recited in claim 4, wherein each of said first and second plurality of openings are respectively spaced from each adjacent opening of said first and second plurality of openings by a distance which is approximately 7 to 8 times greater than said predetermined width. 
     
     
       9. A burner as recited in claim 1, wherein an angle extending in said flow direction and defined by opposite sides of said inner peripheral surface that defines said burner mouth is approximately 80° to 100°. 
     
     
       10. A burner as recited in claim 2, wherein an angle extending in said flow direction and defined by opposite sides of said inner peripheral surface that defines said burner mouth is approximately 80° to 100°. 
     
     
       11. A burner as recited in claim 1, wherein a number of said first and second plurality of openings equals approximately a predetermined throughput volume of the first combustion component divided by 1,250. 
     
     
       12. A burner as recited in claim 2, wherein a number of said first and second plurality of openings equals approximately a predetermined throughput volume of the first combustion component divided by 1,250. 
     
     
       13. A burner as recited in claim 3, wherein a number of said first and second plurality of openings equals approximately a predetermined throughput volume of the first combustion component divided by 1,250. 
     
     
       14. A burner as recited in claim 5, wherein a number of said first and second plurality of openings equals approximately a predetermined throughput volume of the first combustion component divided by 1,250. 
     
     
       15. A burner as recited in claim 1, said wall having a third ring nozzle placing said central burner duct in communication with said outer annular duct for combining the first and second combustion components, said third ring nozzle including a third plurality of openings extending from said outer annular duct and open at said central burner duct, said third ring nozzle being located upstream from said burner mouth relative said flow direction. 
     
     
       16. A burner as recited in claim 15, further comprising a first restrictor plate located in said outer annular duct between said second ring nozzle and said first ring nozzle, and a second restrictor plate located in said outer annular duct between said first ring nozzle and said third ring nozzle. 
     
     
       17. A burner as recited in claim 16, wherein each of said first and second restrictor plates includes an adjustable baffle and is comprised of at least one of a metallic material and a ceramic material. 
     
     
       18. A burner as recited in claim 15, wherein said third ring nozzle is further defined by a first inner peripheral surface of said wall extending inwardly in said central burner duct, said first inner peripheral surface having a decreasing diameter in said flow direction, and a second inner peripheral surface of said wall extending inwardly in said central burner duct, said second inner peripheral surface having an increasing diameter in said flow direction and located downstream from said first inner peripheral surface relative said flow direction, wherein said third plurality of openings open at said second inner peripheral surface of said third ring nozzle. 
     
     
       19. A burner as recited in claim 16, wherein said third ring nozzle is further defined by a first inner peripheral surface of said wall extending inwardly in said central burner duct, said first inner peripheral surface having a decreasing diameter in said flow direction, and a second inner peripheral surface of said wall extending inwardly in said central burner duct, said second inner peripheral surface having an increasing diameter in said flow direction and located downstream from said first inner peripheral surface relative said flow direction, wherein said third plurality of openings open at said second inner peripheral surface of said third ring nozzle. 
     
     
       20. A burner as recited in claim 1, further comprising a plurality of nozzle inserts each adapted for insertion into at least one of said first and second plurality of openings so as to decrease an effective cross-sectional opening area defined by each of said first and second plurality of openings. 
     
     
       21. A burner as recited in claim 15, further comprising a plurality of nozzle inserts each adapted for insertion into at least one of said first and second and third plurality of openings so as to decrease an effective cross-sectional opening area defined by each of said first and second and third plurality of openings. 
     
     
       22. A burner as recited in claim 1, further comprising a plurality of injector grids each adapted for insertion into at least one of said first and second plurality of openings so as to divide said at least one of said first and second plurality of openings into a plurality of smaller openings. 
     
     
       23. A burner as recited in claim 15, further comprising a plurality of injector grids each adapted for insertion into at least one of said first and second and third plurality of openings so as to divide said at least one of said first and second and third plurality of openings into a plurality of smaller openings. 
     
     
       24. A burner as recited in claim 1, wherein said wall comprises refractory bricks enclosed at least in part by a metallic jacket. 
     
     
       25. A burner as recited in claim 15, wherein said wall comprises refractory bricks enclosed at least in part by a metallic band.